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    SubjectRe: Raise initial congestion window size / speedup slow start?
    Ed W wrote:
    >>> Does someone have some pointers on where to look to modify initial
    >>> congestion window please?
    >> Are you sure that's the issue? The backlog is in incoming, is it not?
    > Well, I was simplifying a little bit, actually I have a bunch of
    > protocols in use, http is one of them
    >> Having dealt with moderately long delays push TB between timezones,
    >> have you set your window size up? Set
    >> /proc/sys/net/ipv4/tcp_adv_win_scale to 5 or 6 and see if that helps.
    >> You may have to go into /proc/sys/net/core and crank up the rmem_*
    >> settings, depending on your distribution.
    >> This allows the server to push a lot of data without an ack, which is
    >> what you want, the ack will be delayed by the long latency, so this
    >> helps.
    > I think I'm misunderstanding something fundamental here:
    > - Surely the limited congestion window is what throttles me at
    > connection initialisation time and this will not be affected by
    > changing the params you mention above? For sure the sliding window
    > will be relevant vs my bandwidth delay product once the tcp connection
    > reaches steady state, but I'm mostly worried here about performance
    > right at the creation of the connection?
    > - Both you and Alan mention that the bulk of the traffic is "incoming"
    > - this implies you think it's relevant? Obviously I'm missing
    > something fundamental here because my understanding is that the
    > congestion window shuts us down in both directions (at the start of
    > the connection?)
    > Thanks for the replies - I will take it over to netdev
    Perhaps they will give you an answer you like better.

    Bill Davidsen <>
    "We can't solve today's problems by using the same thinking we
    used in creating them." - Einstein

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